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7 (No Model.) I 2 Sheets-Slieefi M. WADDELL & J. B. ENTZ.

ELECTRIC LOGOMOTIVE. No. 444,512. Patented Jan. 13, 1891.

UNITED STATES PATENT OFFICE.

MONTGOMERY \VADDELL AND JUSTUS B. ENTZ, OF NEW YORK, N. Y.

ELECTRIC LOCOMOTIVE.

SPECIFICATION forming part of Letters Patent No. 4&4512, dated January 13, 1891. Application filed May 20,1890. SerialNo. 352,490. (No model.)

To all whom it may concern.-

Be it known that we, MONTGOMERY WAD- DELL, a subject ofthe Queen of GreatBritain,

'and JUsTUs B. ENTZ, a citizen of the United a sudden relative movement.

In the practical operation of electric railways it is a well known fact that the teeth of the driving-pinion and the gear with which it meshes are subjected to an enormous strain when the current is suddenly passed through the motor. This sudden and continuous strain often causes a rupture of the teeth of these wheels and the consequent disablement of the vehicle.

The object which we seek to attain is accomplished by mounting that part of the motor which is usually stationary and rigidthat is, the field-magnet structure and framein such a manner that it is free to rotate a slight distance on its axis when under severe strain. More specifically stated, the field-magnet structure and frame are loosely mounted upon an axis and are connected through a strong spring with a rigid or stationary portion of the truck or frame. The operation is then: when the current is suddenly put through the motor or a sudden increase of current from any cause flows through the motor, the magnetic attraction between the armature and the pole-pieces will cause the latter, together with the whole field-magnet structure, to give and rotate slightly on its axis, thus relieving the gearing of the strain which would come upon it if the field-magnet structure remained stationary. In other words, the extra torque which the motor-shaft would otherwise assume is taken up by the field-magnet structure. WVe obviously secure the best results when the field-magnet structure and frame are of a symmetrical or balanced shape. We therefore utilize the machine described in the application of \Villiam F. Collins, filed February 18, 1890, and serially numbered 340,905.

Referring now to the accompanying drawings, Figure 1 represents a plan of our improved machinery. Fig. 2 represents a side elevation of the same; Fig. 3, a detail view of spring-box; Fig. 4, a sectional view of the motor, and Fig. 5 a detail of same.

A represents a car-axle carrying the toothed gear-wheel A. V

13 represents a frame of general rectangular shape, which is supported upon the axle at 1) band upon any part of the car body or truck at I). The supports at l) are in the nature of bearings to permit of slight movement of the frame upon the axle, while the support at b may be either a rigid or flexible onethat is to say, a spring may or may not be inserted between the frame B and that portion of the car body or truck which supports it.

0 represents a motor-armature, which is in the form of a Gramme ring, inclosing the fieldmagnet E and pole-pieces 0 G represents the commutator. The armature and commutator are carried by the shaft 0 on the outer end of which is the drivingpinion c, meshing with the gear A on the axle or with an intermediate gear. The bearings for the armature-shaft are formedin the frame B, and they consist of a thimble or sleeve d of gun-metal placed in the box and surrounding the armature-shaft G On the outside of these thimbles short cylindrical projections efrom the field-magn et frame have their bearings.

E E represent a pair of iron spiders connected together by rods or tubes E. One of the spiders E has formed with it or attached to it the interior field-magnet. In general, however, the field-magnet consists of a single coil wound upon an iron core, through which the armature-shaft passes, and having polepieces extending across its ends and overlapping each other across its sides. The outer side of the spiders have formed upon them an outwardly-projectingsleeveorshortcylindere, which extends into the bearing in the frameB and surrounds the gun-m etal thimble or sleeve 01 and is free to turn thereon. The field-magnets are therefore mounted concentrically with the armature. Now each of the bearings is surrounded by a spring-boxf, made in two parts, as shown, one of which is formed with the frame I) and the other as a cap which is bolted to the frame. Inside of this box there is placed a heavy spiral spring f, which is secured at one end to the projecting cylinder 6 and at the other end to the spring box or frame B. This formsa flexible connection between the frame 13 and the field-magnet structure. The strength of these springs is to be such that while the motor is running under normal conditions the springs will resist the pull of the armature upon the fieldmagnets and maintain them in a normal state of tension; but when current is suddenly passed through the motor and the pull between the armature and pole-pieces is above the normal, due to the extra power necessary to overcome the inertia of the car, the springs will give and allow the armature to pull the field-magnets around part way, and thus relieve the teeth of the gearing from this extra strain. Of course the same function is performed when the current through the motor fluctuates or when the load varies.

Having thus described our invention, we claim 1. In a dynamo-electric machine, a pair of circular frames or spiders connected at their edges to form a cylindrical space within, fieldmagnets in said space and supported by the frames or spiders, and an armature rotating within said space.

2. In a dynamo-electric machine, a pair of circular frames or spiders connected at their edges to form a cylindrical space within, fieldmagnets in said space and supported by the frames or spiders, and an armature rotating within said space, the shaft of the armature extending concentrically through the said frames or spiders, and a spring or springs connecting the frames or spiders with a fixed support, for the purpose set forth.

3. In a motor-truck for vehicles, the combination of a frame for supporting the motor, bearings in the same for the motor-shaft, an electric motor whose stationary element is mounted concentrically and in the same bearings with the main shaft, and a spiral spring surrounding the journal ofsaid stationary element, the spring being secured at one end to the journal and at the other end to the frame.

In witness whereof we have hereunto afiixed our seals and signed our names in the presence of two subscribing witnesses.

MONTGOMERY WADDELL. [L. S.] JUS'IUS B. EN'IZ. [rt 8.] Vitnesses:

THos. H. FOOTE, E. J. WHEELER. 

